<p>This tutorial introduces JOIN which allows you to use data from two or more tables. The tables contain all matches and goals from UEFA EURO 2012 Football Championship in Poland and Ukraine.</p>

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<p>This tutorial introduces <code>JOIN</code> which allows you to use data from two or more tables. The tables contain all matches and goals from UEFA EURO 2012 Football Championship in Poland and Ukraine.</p>

<div class="progress_panel"><div>

<div class="progress_panel"><div>

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<div class='qu'>

<div class='qu'>

From the previous query you can see that Lars Bender's goal was scored in game 1012.

From the previous query you can see that Lars Bender's goal was scored in game 1012.

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Notice that the column '''matchid''' in the '''goal''' table corresponds to the '''id''' column in the '''game''' table.

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Notice that the column <code>matchid</code> in the <code>goal</code> table corresponds to the <code>id</code> column in the <code>game</code> table.

<p class='imper'>Show id, stadium, team1, team2 for game 1012</p>

<p class='imper'>Show id, stadium, team1, team2 for game 1012</p>

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SELECT id,stadium,team1,team2

SELECT id,stadium,team1,team2

FROM game

FROM game

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WHERE id=1023</source>

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WHERE id=1012</source>

</div>

</div>

<div class='qu'>

<div class='qu'>

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You can combine the two steps into a single query with a join. You will get all the '''game''' details and all the '''goal''' details if you use

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You can combine the two steps into a single query with a <code>JOIN</code>. You will get all the <code>game</code> details and all the <code>goal</code> details if you use

SELECT *

SELECT *

FROM game JOIN goal ON (id=matchid)

FROM game JOIN goal ON (id=matchid)

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<div class='qu'>

<div class='qu'>

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Use the same join as in the previous question.

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Use the same <code>JOIN</code> as in the previous question.

<p class='imper'>Show the team1, team2 and player for every goal scored by a player called Mario <code>player LIKE 'Mario%'</code></p>

<p class='imper'>Show the team1, team2 and player for every goal scored by a player called Mario <code>player LIKE 'Mario%'</code></p>

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<div class='qu'>

<div class='qu'>

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The table '''eteam''' gives details of every national team including the coach. You can JOIN '''goal''' to '''eteam''' using the phrase <code>goal JOIN eteam on teamid=id</code>

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The table <code>eteam</code> gives details of every national team including the coach. You can <code>JOIN</code> <code>goal</code> to <code>eteam</code> using the phrase <code>goal JOIN eteam on teamid=id</code>

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<p class='imper'>Show player, teamid, coach, gtime for all goals scored in the first 10 minutes <code>gtime&lt;=10</code></p>

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<p class='imper'>Show <code>player</code>, <code>teamid</code>, <code>coach</code>, <code>gtime</code> for all goals scored in the first 10 minutes <code>gtime&lt;=10</code></p>

<source lang='sql' class='def'>

<source lang='sql' class='def'>

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<div class='qu'>

<div class='qu'>

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To JOIN '''game''' with '''eteam''' you could use either<br/> <code>game JOIN eteam ON (team1=eteam.id)</code> or <code>game JOIN eteam ON (team2=eteam.id)</code>

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To <code>JOIN</code> <code>game</code> with <code>eteam</code> you could use either<br/> <code>game JOIN eteam ON (team1=eteam.id)</code> or <code>game JOIN eteam ON (team2=eteam.id)</code>

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Notice that because '''id''' is a column name in both '''game''' and '''eteam''' you must specify '''eteam.id''' instead of just '''id'''

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Notice that because <code>id</code> is a column name in both <code>game</code> and <code>eteam</code> you must specify <code>eteam.id</code> instead of just <code>id</code>

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<p class='imper'>List the dates of the matches in which 'Fernando Santos' was the team1 coach.</p>

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<p class='imper'>List the the dates of the matches and the name of the team in which 'Fernando Santos' was the team1 coach.</p>

<source lang='sql' class='def'>

<source lang='sql' class='def'>

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<div class='qu'>

<div class='qu'>

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The example shows result of the final match. <code>COUNT()</code> has been used to count the total number of goals.<br/>

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<div class='imper'>Show '''team1''', '''team2''' and results of all matches played at 'PGE Arena Gdansk' stadium.</div>

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<div class='imper'>Show '''teamname''' and the total number of goals scored.</div>

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<div class="hint" title="COUNT and GROUP BY">

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You should COUNT(*) in the SELECT line and GROUP BY teamname

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</div>

<source lang='sql' class='def'>

<source lang='sql' class='def'>

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select team1, team2,

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SELECT teamname, player

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(select count(*) from goal

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FROM eteam JOIN goal ON id=teamid

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where matchid = id AND teamid = team1)

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ORDER BY teamname

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as team1,

+

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(select count(*) from goal

+

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where matchid = id AND teamid = team2)

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as team2

+

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FROM game WHERE id = 1031

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</source>

</source>

<source lang='sql' class='ans'>

<source lang='sql' class='ans'>

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select team1, team2,

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SELECT teamname,COUNT(teamid)

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(select count(*) from goal

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FROM eteam JOIN goal ON id=teamid

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where matchid = id AND teamid = team1)

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GROUP BY teamname

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as team1,

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(select count(*) from goal

+

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where matchid = id AND teamid = team2)

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as team2

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FROM game WHERE stadium = 'PGE Arena Gdansk'

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</source>

</source>

</div>

</div>

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<div class='qu'>

<div class='qu'>

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The following query shows matches which were won by team1.

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<div class='imper'>Show the stadium and the number of goals scored in each stadium.

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<div class='imper'>Show '''id''' of matches in which '''team1''' scored at least two more goals than '''team2'''.

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</div>

</div>

<source lang='sql' class='def'>

<source lang='sql' class='def'>

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select team1, team2 FROM game WHERE

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</source>

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(select count(*) from goal

+

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where matchid = id AND teamid = team1) >

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(select count(*) from goal

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where matchid = id AND teamid = team2)</source>

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<source lang='sql' class='ans'>

<source lang='sql' class='ans'>

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select id FROM game WHERE

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SELECT stadium,COUNT(1)

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(select count(*) from goal

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FROM goal JOIN game ON id=matchid

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where matchid = id AND teamid = team1) -

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GROUP BY stadium</source>

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(select count(*) from goal

+

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where matchid = id AND teamid = team2) >= 2</source>

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</div>

</div>

<div class='qu'>

<div class='qu'>

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The example shows teams that scored a goal at stadiums where Poland has played its matches.

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<div class='imper'>For every match involving 'POL', show the matchid, date and the number of goals scored.</div>

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<div class='imper'>Show '''players''' that scored a goal at 'National Stadium, Warsaw' in a day ('''mdate''') when Czech Republic ('CZE') didn't play a match. Use <code>DISTINCT</code> to remove duplicates from your query results.</div>

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<source lang='sql' class='def'>

<source lang='sql' class='def'>

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SELECT distinct teamid

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SELECT matchid,mdate, team1, team2,teamid

FROM game JOIN goal ON matchid = id

FROM game JOIN goal ON matchid = id

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WHERE Stadium IN

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WHERE (team1 = 'POL' OR team2 = 'POL')

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(SELECT stadium FROM game

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WHERE team1 = 'POL' OR team2 = 'POL')

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</source>

</source>

<source lang='sql' class='ans'>

<source lang='sql' class='ans'>

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SELECT DISTINCT player

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SELECT matchid,mdate,COUNT(teamid)

FROM game JOIN goal ON matchid = id

FROM game JOIN goal ON matchid = id

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WHERE stadium = 'National Stadium, Warsaw'

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WHERE (team1 = 'POL' OR team2 = 'POL')

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AND mdate NOT IN

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GROUP BY matchid,mdate

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(SELECT mdate FROM game

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WHERE team1 = 'CZE' OR team2 = 'CZE')

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</source>

</source>

</div>

</div>

<div class='qu'>

<div class='qu'>

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The query shows the stadiums, where the teams who scored more than 8 goals played their matches.

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<div class='imper'>Show '''teamid''' and '''count of goals''' for all 8 teams that have played more than 3 matches.</div>

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<div class='imper'>For every match where 'GER' scored, show matchid, match date and the number of goals scored by 'GER'</div>

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<source lang='sql' class='def'>

+

</source>

<source lang='sql' class='ans'>

<source lang='sql' class='ans'>

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SELECT teamid, count(*) FROM goal

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SELECT matchid,mdate,COUNT(teamid)

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WHERE 3 <

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FROM game JOIN goal ON matchid = id

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(SELECT COUNT(distinct id) FROM game

+

WHERE (teamid='GER')

−

WHERE team1 = teamid OR team2 = teamid)

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GROUP BY matchid,mdate

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group by teamid

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</source>

</source>

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</div>

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<div>

+

<div class='qu'>

+

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<div class='imper'>List every match with the goals scored by each team as shown.</div>

Notice in the query given every goal is listed. If it was a team1 goal then a 1 appears in score1, otherwise there is a 0. You could SUM this column to get a count of the goals scored by team1. '''Sort your result by mdate, matchid, team1 and team2.'''

<source lang='sql' class='def'>

<source lang='sql' class='def'>

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SELECT distinct stadium

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SELECT mdate,

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FROM game WHERE team1 IN

+

team1,

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(SELECT teamid FROM goal

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CASE WHEN teamid=team1 THEN 1 ELSE 0 END score1

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group by teamid having count(*) > 8)

+

FROM game JOIN goal ON matchid = id

</source>

</source>

+

+

<source lang='sql' class='ans'>

+

SELECT mdate,

+

team1,

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SUM(CASE WHEN teamid=team1 THEN 1 ELSE 0 END) score1,

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team2,

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SUM(CASE WHEN teamid=team2 THEN 1 ELSE 0 END) score2

+

FROM game JOIN goal ON matchid = id

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GROUP BY mdate,matchid,team1,team2

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</source>

+

</div>

</div>

<div>

<div>

Revision as of 08:51, 13 February 2013

game

id

mdate

stadium

team1

team2

1001

8 June 2012

National Stadium, Warsaw

POL

GRE

1002

8 June 2012

Stadion Miejski (Wroclaw)

RUS

CZE

1003

12 June 2012

Stadion Miejski (Wroclaw)

GRE

CZE

1004

12 June 2012

National Stadium, Warsaw

POL

RUS

...

goal

matchid

teamid

player

gtime

1001

POL

Robert Lewandowski

17

1001

GRE

Dimitris Salpingidis

51

1002

RUS

Alan Dzagoev

15

1001

RUS

Roman Pavlyuchenko

82

...

eteam

id

teamname

coach

POL

Poland

Franciszek Smuda

RUS

Russia

Dick Advocaat

CZE

Czech Republic

Michal Bilek

GRE

Greece

Fernando Santos

...

JOIN and UEFA EURO 2012

This tutorial introduces JOIN which allows you to use data from two or more tables. The tables contain all matches and goals from UEFA EURO 2012 Football Championship in Poland and Ukraine.

Summary

The first example shows the goal scored by 'Bender'.

Show matchid and player name for all goals scored by Germany.
teamid = 'GER'

SELECT*FROM goal
WHERE player LIKE'%Bender'

SELECT matchid, player
FROM goal
WHERE teamid LIKE'GER'

From the previous query you can see that Lars Bender's goal was scored in game 1012.
Notice that the column matchid in the goal table corresponds to the id column in the game table.

Show id, stadium, team1, team2 for game 1012

SELECT id,stadium,team1,team2
FROM game
WHERE stadium LIKE'%Warsaw%'

SELECT id,stadium,team1,team2
FROM game
WHERE id=1012

You can combine the two steps into a single query with a JOIN. You will get all the game details and all the goal details if you use

SELECT *
FROM game JOIN goal ON (id=matchid)

Show the player, teamid and mdate and for every German goal. teamid='GER'

Notice in the query given every goal is listed. If it was a team1 goal then a 1 appears in score1, otherwise there is a 0. You could SUM this column to get a count of the goals scored by team1. Sort your result by mdate, matchid, team1 and team2.